From: Fiona Ebner <f.ebner@proxmox.com>
To: pve-devel@lists.proxmox.com
Subject: [pve-devel] [PATCH qemu 1/2] fix #4476: savevm-async: avoid looping without progress
Date: Thu, 26 Jan 2023 14:46:13 +0100 [thread overview]
Message-ID: <20230126134614.117709-1-f.ebner@proxmox.com> (raw)
when pend_postcopy is large. By definition, pend_postcopy won't
decrease when iterating, so a value larger than the cutoff of 400000
would lead to essentially empty iterations, filling up the state file
until only 30 MiB + pending_size remain and the second half of the
check would trigger.
Avoid this, by not considering pend_postcopy for the cutoff to enter
the final phase.
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
Many thanks to Fabian for discussing the issue with me!
...vevm-async-for-background-state-snapshots.patch | 14 ++++++++------
...-PVE-add-optional-buffer-size-to-QEMUFile.patch | 6 +++---
...async-register-yank-before-migration_inco.patch | 4 ++--
3 files changed, 13 insertions(+), 11 deletions(-)
diff --git a/debian/patches/pve/0017-PVE-add-savevm-async-for-background-state-snapshots.patch b/debian/patches/pve/0017-PVE-add-savevm-async-for-background-state-snapshots.patch
index fcbe4bc..91d4710 100644
--- a/debian/patches/pve/0017-PVE-add-savevm-async-for-background-state-snapshots.patch
+++ b/debian/patches/pve/0017-PVE-add-savevm-async-for-background-state-snapshots.patch
@@ -24,7 +24,8 @@ Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
[improve aborting]
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
[FE: further improve aborting
- adapt to removal of QEMUFileOps]
+ adapt to removal of QEMUFileOps
+ improve condition for entering final stage]
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
hmp-commands-info.hx | 13 +
@@ -32,13 +33,13 @@ Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
include/migration/snapshot.h | 2 +
include/monitor/hmp.h | 5 +
migration/meson.build | 1 +
- migration/savevm-async.c | 531 +++++++++++++++++++++++++++++++++++
+ migration/savevm-async.c | 532 +++++++++++++++++++++++++++++++++++
monitor/hmp-cmds.c | 57 ++++
qapi/migration.json | 34 +++
qapi/misc.json | 32 +++
qemu-options.hx | 12 +
softmmu/vl.c | 10 +
- 11 files changed, 730 insertions(+)
+ 11 files changed, 731 insertions(+)
create mode 100644 migration/savevm-async.c
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
@@ -154,10 +155,10 @@ index 8cac83c06c..0842d00cd2 100644
), gnutls)
diff --git a/migration/savevm-async.c b/migration/savevm-async.c
new file mode 100644
-index 0000000000..05d394c0e2
+index 0000000000..4a4e91a26d
--- /dev/null
+++ b/migration/savevm-async.c
-@@ -0,0 +1,531 @@
+@@ -0,0 +1,532 @@
+#include "qemu/osdep.h"
+#include "migration/channel-savevm-async.h"
+#include "migration/migration.h"
@@ -415,7 +416,8 @@ index 0000000000..05d394c0e2
+
+ maxlen = blk_getlength(snap_state.target) - 30*1024*1024;
+
-+ if (pending_size > 400000 && snap_state.bs_pos + pending_size < maxlen) {
++ /* Note that there is no progress for pend_postcopy when iterating */
++ if (pending_size - pend_postcopy > 400000 && snap_state.bs_pos + pending_size < maxlen) {
+ ret = qemu_savevm_state_iterate(snap_state.file, false);
+ if (ret < 0) {
+ save_snapshot_error("qemu_savevm_state_iterate error %d", ret);
diff --git a/debian/patches/pve/0018-PVE-add-optional-buffer-size-to-QEMUFile.patch b/debian/patches/pve/0018-PVE-add-optional-buffer-size-to-QEMUFile.patch
index 5cf894b..956a09d 100644
--- a/debian/patches/pve/0018-PVE-add-optional-buffer-size-to-QEMUFile.patch
+++ b/debian/patches/pve/0018-PVE-add-optional-buffer-size-to-QEMUFile.patch
@@ -192,10 +192,10 @@ index fa13d04d78..914f1a63a8 100644
int qemu_fclose(QEMUFile *f);
diff --git a/migration/savevm-async.c b/migration/savevm-async.c
-index 05d394c0e2..bafe6ae5eb 100644
+index 4a4e91a26d..20aae335ca 100644
--- a/migration/savevm-async.c
+++ b/migration/savevm-async.c
-@@ -367,7 +367,7 @@ void qmp_savevm_start(bool has_statefile, const char *statefile, Error **errp)
+@@ -368,7 +368,7 @@ void qmp_savevm_start(bool has_statefile, const char *statefile, Error **errp)
QIOChannel *ioc = QIO_CHANNEL(qio_channel_savevm_async_new(snap_state.target,
&snap_state.bs_pos));
@@ -204,7 +204,7 @@ index 05d394c0e2..bafe6ae5eb 100644
if (!snap_state.file) {
error_set(errp, ERROR_CLASS_GENERIC_ERROR, "failed to open '%s'", statefile);
-@@ -500,7 +500,8 @@ int load_snapshot_from_blockdev(const char *filename, Error **errp)
+@@ -501,7 +501,8 @@ int load_snapshot_from_blockdev(const char *filename, Error **errp)
blk_op_block_all(be, blocker);
/* restore the VM state */
diff --git a/debian/patches/pve/0049-PVE-savevm-async-register-yank-before-migration_inco.patch b/debian/patches/pve/0049-PVE-savevm-async-register-yank-before-migration_inco.patch
index b25c9fc..746b735 100644
--- a/debian/patches/pve/0049-PVE-savevm-async-register-yank-before-migration_inco.patch
+++ b/debian/patches/pve/0049-PVE-savevm-async-register-yank-before-migration_inco.patch
@@ -11,7 +11,7 @@ Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
1 file changed, 5 insertions(+)
diff --git a/migration/savevm-async.c b/migration/savevm-async.c
-index bafe6ae5eb..da3634048f 100644
+index 20aae335ca..94c5ae1c81 100644
--- a/migration/savevm-async.c
+++ b/migration/savevm-async.c
@@ -20,6 +20,7 @@
@@ -22,7 +22,7 @@ index bafe6ae5eb..da3634048f 100644
/* #define DEBUG_SAVEVM_STATE */
-@@ -514,6 +515,10 @@ int load_snapshot_from_blockdev(const char *filename, Error **errp)
+@@ -515,6 +516,10 @@ int load_snapshot_from_blockdev(const char *filename, Error **errp)
dirty_bitmap_mig_before_vm_start();
qemu_fclose(f);
--
2.30.2
next reply other threads:[~2023-01-26 13:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-26 13:46 Fiona Ebner [this message]
2023-01-26 13:46 ` [pve-devel] [PATCH qemu 2/2] savevm-async: keep more free space when entering final stage Fiona Ebner
2023-02-09 9:30 ` [pve-devel] [PATCH qemu 1/2] fix #4476: savevm-async: avoid looping without progress Fiona Ebner
2023-02-21 8:15 ` [pve-devel] applied-series: " Thomas Lamprecht
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230126134614.117709-1-f.ebner@proxmox.com \
--to=f.ebner@proxmox.com \
--cc=pve-devel@lists.proxmox.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox